How Mushrooms Can Save the World

Technicians from a Seattle-based bioremediation company, Enviros, learned of Stamets’ success and asked him for advice on using fungi to clean up oil-soaked soil. At the time, many experts were betting on hydrocarbon-eating bacteria as an eco-friendlier alternative to the conventional way of cleaning up such contamination — which was to truck the affected soil to a landfill and replace it with clean dirt. But bacteria can have trouble breaking down petroleum’s largest molecules, and they’re finicky about ambient temperature and oxygen levels.

A few researchers had begun experimenting with fungi instead. It had long been known that mold and mushroom species called “white rot” fungi could eat the lignin in wood, using enzymes to convert its complex hydrocarbons into nutritious carbohydrates. Molds also sometimes colonize fuel tanks, where they use those same enzymes to consume petroleum products.

In the lab, a white-rot mold called Phanerochaete chrysoporium had shown particular thoroughness at digesting oil, but it often failed to perform under outdoor conditions. The Enviros staff hoped to find a hardier fungus, and Stamets suggested they try oyster mushrooms (Pleurotus ostreatus), an aggressive white-rotter that could grow practically anywhere. He sent them some oyster mushroom spawn. The technicians covered it with oil, most of which was consumed within three weeks; mushrooms were popping up through the muck